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author | 2021-08-12 21:03:24 +0200 | |
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committer | 2021-08-12 21:03:24 +0200 | |
commit | 98263a7de64269898a2f81207e38943b5c8e8653 (patch) | |
tree | 743c90f109a6c5d27832d1dcef2388d939f0f77a /vendor/github.com/wagslane/go-password-validator/entropy.go | |
parent | Text duplication fix (#137) (diff) | |
download | gotosocial-98263a7de64269898a2f81207e38943b5c8e8653.tar.xz |
Grand test fixup (#138)
* start fixing up tests
* fix up tests + automate with drone
* fiddle with linting
* messing about with drone.yml
* some more fiddling
* hmmm
* add cache
* add vendor directory
* verbose
* ci updates
* update some little things
* update sig
Diffstat (limited to 'vendor/github.com/wagslane/go-password-validator/entropy.go')
-rw-r--r-- | vendor/github.com/wagslane/go-password-validator/entropy.go | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/vendor/github.com/wagslane/go-password-validator/entropy.go b/vendor/github.com/wagslane/go-password-validator/entropy.go new file mode 100644 index 000000000..340dac270 --- /dev/null +++ b/vendor/github.com/wagslane/go-password-validator/entropy.go @@ -0,0 +1,39 @@ +package passwordvalidator + +import ( + "math" +) + +// GetEntropy returns the entropy in bits for the given password +// See the ReadMe for more information +func GetEntropy(password string) float64 { + return getEntropy(password) +} + +func getEntropy(password string) float64 { + base := getBase(password) + length := getLength(password) + + // calculate log2(base^length) + return logPow(float64(base), length, 2) +} + +func logX(base, n float64) float64 { + if base == 0 { + return 0 + } + // change of base formulae + return math.Log2(n) / math.Log2(base) +} + +// logPow calculates log_base(x^y) +// without leaving logspace for each multiplication step +// this makes it take less space in memory +func logPow(expBase float64, pow int, logBase float64) float64 { + // logb (MN) = logb M + logb N + total := 0.0 + for i := 0; i < pow; i++ { + total += logX(logBase, expBase) + } + return total +} |